That's an excellent question! There is only one major disease that a female would need to be concerned about when cleaning litter boxes. That disease is called toxplasmosis and it is only dangerous to pregnant women. It won't harm the mother, but it could cause problems for the fetus. Fortunately, it is VERY easy to avoid contracting this disease with just a little common sense. If possible, during pregnancy, have someone else clean the box. If that is not an option, use disposable rubber gloves when cleaning and wash up thoroughly after disposing of dirty litter. A woman would need to ingest infected stool in order to contract this disease, and of course, the cat would actually have to have the disease. A simple blood test can diagnose the disease in a cat and those which stay indoors and don't have contact with rodents have little chance of contracting toxo.
Please let me know if I can help further in any way.